how to fix Honda Civic 10th Generation (2016-2021) P0171 code

Solution

1. Preparation

• Tools Required: OBD-II scanner, vacuum gauge, fuel pressure gauge, socket set, torque wrench, multimeter, cleaning solvent, safety goggles, gloves.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect vacuum hoses and connections for cracks or disconnections.
  2. Use a vacuum gauge to test the intake manifold vacuum. Values should be within 17-21 inHg at idle.
  3. If a leak is found, replace the damaged hose or re-establish the connection.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector carefully.
  3. Remove the MAF sensor using the appropriate socket size.
  4. Clean the MAF sensor with a specialized MAF cleaner spray and allow it to dry completely.
  5. Reinstall the MAF sensor and reconnect the electrical connector.

4. Check Fuel Pressure

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition key to the ON position (do not start the engine) and check the fuel pressure. It should be within the range specified in the service manual (usually around 40-50 psi).
  3. If the pressure is low, check the fuel pump operation and fuel filter condition; replace if necessary.

5. Inspect Fuel Injectors

• Sub-steps:
  1. Access the fuel injectors by removing the intake manifold if needed.
  2. Visually inspect for leaks or physical damage.
  3. Use a multimeter to check the resistance of each injector. Values should typically be between 12-16 ohms.
  4. Clean or replace defective injectors as necessary.

6. Reconnect Battery and Clear Codes

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0171 code.
  3. Perform a test drive to monitor the engine’s performance.